private async void btnWrite_Click(object sender, RoutedEventArgs e){    await WriteToFile();    // Update UI.    this.btnWrite.IsEnabled = false;    this.btnRead.IsEnabled = true;}private async Task WriteToFile(){    // Get the text data from the textbox.     byte[] fileBytes = System.Text.Encoding.UTF8.GetBytes(this.textBox1.Text.ToCharArray());    // Get the local folder.    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;    // Create a new folder name DataFolder.    var dataFolder = await local.CreateFolderAsync("DataFolder",        CreationCollisionOption.OpenIfExists);    // Create a new file named DataFile.txt.    var file = await dataFolder.CreateFileAsync("DataFile.txt",    CreationCollisionOption.ReplaceExisting);    // Write the data from the textbox.    using (var s = await file.OpenStreamForWriteAsync())    {        s.Write(fileBytes, 0, fileBytes.Length);    }}

private async void btnRead_Click(object sender, RoutedEventArgs e){    await ReadFile();    // Update UI.    this.btnWrite.IsEnabled = true;    this.btnRead.IsEnabled = false;}private async Task ReadFile(){    // Get the local folder.    StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;    if (local != null)    {        // Get the DataFolder folder.        var dataFolder = await local.GetFolderAsync("DataFolder");        // Get the file.        var file = await dataFolder.OpenStreamForReadAsync("DataFile.txt");        // Read the data.        using (StreamReader streamReader = new StreamReader(file))        {            this.textBlock1.Text = streamReader.ReadToEnd();        }    }}